The present disclosure relates generally to the field of image or brightness and/or contrast control in display systems. More particularly, the present disclosure relates to image control for translucent and non-translucent displays.
Displays are utilized in a wide variety of applications including but not limited to medical, military, avionic, entertainment and computing applications. In one exemplary application, translucent or transparent displays are used in conjunction with non-translucent or non-transparent displays. Translucent displays allow a user to view an environment behind the display of information. Translucent displays include but are not limited to: head up display (HUD) systems and wearable displays, such as, helmet mounted display (HMD) systems. Non-translucent displays include but are not limited to: cathode ray tubes (CRT), backlit liquid crystal display (LCD), and projection systems where the user does not view objects behind the screen of the display. As used herein, the term translucent display includes transparent displays and the term non-translucent display includes non-transparent displays.
In aircraft applications, head up display systems and helmet mounted display systems allow the flight crew to maintain eye contact with the outside environment while simultaneously viewing information from aircraft systems and sensors in a graphical and alphanumeric format overlaying the outside world view. Head up display systems are known to provide conformal information such that displayed features overlay the environmental view. The displayed features can be sourced from a head up display computer, from a camera or other imaging sensor (such as a visible light imaging sensor, infrared imaging sensor, millimeter wave radar imager, etc.), or from a synthetic vision source. In aircraft applications, head down display (HDDs) systems are non-translucent displays that provide display information from aircraft instruments (e.g., traffic collision avoidance systems (TCAS), weather radar systems, flight management computers (FMC), flight instrumentation, etc.), from a camera or other imaging sensor (such as a visible light imaging sensor, infrared imaging sensor, millimeter wave radar imager, etc.), or from a synthetic vision source. Head up display systems and head down display systems also often display additional information related to aircraft controls, sensors, instruments, etc.
Conventional avionic systems with a head up display system and a head down display system generally include an independent control knob for brightness for the head up display system, an independent control knob for contrast for the head up display system, an independent control knob for brightness for the head down display system, and an independent control knob for contrast for the head down display system. Such independent control is used to provide image appearance control for images displayed on head up display systems and head down display systems and is conventionally believed to be necessary due to the different nature of those displays. Requirements for display image appearance are generally different for the translucent display system and the non-translucent display system because less obscuration of the environment viewable through the display in the translucent display system is desirable and more detail on the display in the non-translucent display system is desirable.
Independent contrast and/or brightness control for translucent display systems and non-translucent systems can be impractical or unfeasible. For example, in avionics applications, processing imagery through independent channels for enhanced, synthetic, and combination images adds to the cost of the avionic display system. Further, independent contrast and/or brightness control for head up display systems and head down display systems also adds to the pilot's cockpit resource management (CRM) tasks. Further still, independent contrast and/or brightness control for head up display systems and head down display systems provide a less consistent set of images to the user or pilot.
Accordingly, there is a need for a system and method of providing an optimal degree of brightness and/or contrast with minimal adjustments from a user for translucent and non-translucent display systems. There is a further need for systems for and methods of controlling image quality for translucent and non-translucent display systems without requiring a two knob interface. There is still a further need for systems for and methods of controlling brightness and contrast with a less complex user interface for head up display systems and head down display systems in an avionic environment. Yet further, there is a need for unified image control for head up display systems and head down display systems. There is also a need for a unified method for control of head-up and head-down display system brightness that, with a single setting, accomplishes the task of simultaneously balancing image appearance on the head up and head down display and provides the same image to different crewmembers who might be utilizing different head up or head down display systems. Finally, a unified method for control of head-up and head-down display system brightness that with a single setting accomplishes the task of simultaneously balancing image appearance on the head up and head down display is desirable in order to provide the same image to different crewmembers who might be utilizing different head up or head down display systems.